The Order Received email template ignores the HTML template assigned and sends the email as before. To reproduce:
1. Update Order Received plugin template to use the "Default Template" for HTML Template.
2. Place an order as a client (with staff subscribed).
3. Note that the email arrives without the HTML template's header/footer
Separately, there is a mobile version of this template but since it is intended for mobile devices it would not be good in most cases to set this email to use a template at all. However, if one is set we should probably honor that.
Check that the Affiliate emails, Abandoned Order emails also observe the HTML Template.
Big Question! Do any other plugin email templates ignore the HTML template? If so, we need to create tasks for and update them also. (Domain Manager? Support Manager ticket emails do observe)